Field of the Invention
The present invention relates generally to firearms, and more particularly toward a manually reciprocated gun stock or handle for enabling controlled rapid fire of a semi-automatic firearm.
Description of Related Art
Various techniques and devices have been developed to increase the firing rate of semi-automatic firearms. Slide Fire Solutions LP, of Moran, Tex., Applicant of this present invention, markets a proprietary slide-action stock under the registered trademark SLIDE FIRE. The SLIDE FIRE® slide-action stock is described for example in detail in US 2012/0240442, published Sep. 27, 2012 and US 2012/0311907 published Dec. 13, 2012, the entire disclosures of which are hereby incorporated by reference and relied upon.
The slide-action stocks in these exemplary citations include a shoulder stock portion having a rearwardly facing butt end that is adapted to be pressed into the shoulder of a user, a pistol grip portion adapted to be grasped by the user's hand, and a finger rest configured to stabilize the end of a user's trigger finger stretched in front of the trigger of the firearm while the remaining fingers of the user's hand clench the pistol grip. The shoulder stock and pistol grip and finger rest are fixed together as a monolithic handle unit that, in use, is held tight to the user's body. When used in a rapid-fire slide-action mode of operation, the handle unit supports a firing unit portion of the firearm—namely the barrel, receiver and trigger—for manual reciprocation back-and-forth over a short (e.g., about one inch) travel distance. In the hands of a practiced and responsible user, the handle unit allows the reciprocation of the firing unit to be timed in counterpoise with the recoil from each fired round of ammunition, which in turn allows a very short time interval between each successive round fired.
In the prior art examples, the distance between the butt end of the shoulder stock and the finger rest is non-adjustable. That is, the trigger pull length, which is generally defined as the distance between butt end of the shoulder stock and the trigger in a rifle, is non-adjustable. As a result, users with exceptionally long or short arms, or that wear especially thick clothing, could find the firearm fit to be less than ideal. Shooting accuracy may suffer as a result of poor fit.
Adjustable and/or collapsible shoulder stocks are made for non-slide-action semi-automatic long rifles, including as two examples those produced by Magpul, Inc. and Tapco, Inc. Such prior art adjustable shoulder stocks usually include a lever-actuated latch that is manipulated by the user to selectively place a small plunger in any one of several adjustment holes aligned in a row along the bottom of a buffer tube (or of a comparable shaft-like feature) that extends rearwardly from the firearm receiver. To adjust the shoulder stock length, i.e., the trigger pull length, a user manually withdraws the plunger (via the lever actuator of the latch) then slides the shoulder stock to a preferred adjusted length position. Upon release of the lever actuator, the plunger seats itself in the nearest adjustment hole thus securing the shoulder stock in the length-adjusted position.
Such prior art adjustable shoulder stocks are generally incompatible with slide-action reciprocating handles. For one reason, slide-action handles may use the same row of adjustment holes along the buffer tube (or comparable shaft-like feature) as a lock-out feature to selectively impede the slide-action mode of operation. Another reason that prior art adjustable shoulder stocks have been deemed incompatible with a slide-action reciprocating handles is that there has been no effective way to couple the prior art adjustable stock to the pistol grip and to a finger rest as a monolithic handle unit while incorporating a reciprocating interface with the firing unit portion of the firearm. While those not well-acquainted with the art may naively suppose design of an adjustable slide-action handle to be a relatively straightforward engineering exercise, such is in fact not at all readily apparent to the skilled artisan due, at least in part, to the requirements that shoulder stock and pistol grip be integrated into a monolithic handle unit that, in use, remains held tight to the user's body while the firing unit portion of the firearm rapidly reciprocates back-and-forth. A still further reason that prior art adjustable shoulder stocks have been deemed incompatible with slide-action reciprocating handles is that a prior art adjustable shoulder stock is intended to be locked relative to the firing unit in an adjusted position for use. A shoulder stock locked in position relative to the firing unit would impede slide-action shooting.
Another shortcoming that exists in prior art slide-action stocks has been the fact that different stock designs are required to accommodate left-handed and right-handed shooters. A right-handed shooter wants the finger rest to be located on the left side of the trigger. Conversely, a left-handed shooter wants the finger rest to be located on the right side of the trigger.
A still further shortcoming that exists in prior art slide-action stocks has been raised by competitive shooters that require a solid, stable connection between handle and firing unit. That is to say, for some users that shoot at a slow pace in normal semi-automatic mode, any degree of play between firing unit and handle could pose a concern. However, a slide-action handle required there to be at least a running fit clearance to allow the firing unit to rapidly reciprocate within the handle. Too tight of a fit will not only impede the raid-fire, slide-action mode of operation, but also possibly result in accelerated wear of the sliding components.
And yet another shortcoming that exists in prior art slide-action stocks has been identified by some in the location of the slide-action lock-out feature. As mentioned above, there may be times when a user wants to operate the firearm in a traditional, semi-automatic mode firing rounds of ammunition at a relatively slow cadence. In these situations, the user may wish to arrest all longitudinal reciprocating action between the handle and the firing unit. The prior art has taught to incorporate a lock-out feature for this purpose at a mid-point location between butt end and pistol grip. The location of the prior art lock-out features and generated concerns by some users, as being not optimally ergonomic.
Therefore, there exists a continuing need for further improvements in devices that will allow a firearms user to practice slide-action shooting in the most effective manner possible, and in which users of varying arm lengths may experience the sport with proper fit, and in which left-handed and right-handed shooters can enjoy by sharing use of the same firearm, and in which competitive shooters can practice carefully aimed shots from a solid, stable handle, and where the lock-out feature is more ergonomic and versatile.